Is it possible to install 2 different versions of an application at the same time

It completely depends on how the software is written. Some do, some don't.

• If when you install the latest version it implements a library/file/registry entry in the same location as the older version and that library/file/registry entry is incompatible it will break the older version.

• If it doesn't, you should be fine.

Your best bet would be to ask the Virtual Box people themselves.

In general software you can often get away with it (depending on what operating system your running and how you configure things).

However, this is VirtualBox. DO NOT RUN TWO VERSIONS AT ONCE. They will almost certainly conflict. Especially if you are using hardware assisted virtualization (VTX).